Xanthen derivatives

ABSTRACT

N-alkyl-N-9-xanthenylurea and substituted derivatives thereof useful in the treatment of peptic ulcer.

United States Patent 1191 Adams et al.

[ Dec. 16, 1975 1 XANTHEN DERIVATIVES [75] Inventors: Stuart Sanders Adams; Bernard John Armitage; Norman William Bristow; Bernard Vincent Heathcote, all of Nottingham,

England [73] Assignee: The Boots Company Limited,

England [22] Filed: Oct. 23, 1973 [21] Appl. No.: 408,378

Related U.S. Application Data [63] Continuation of Ser. No. 191,112, on. 20, 1971, abandoned, which is a continuation-in-part of Ser. No. 662,587, Aug 23, 1967, Pat. No. 3,644,420.

[30] Foreign Application Priority Data Sept. 2, 1966 United Kingdom 39384/66 Apr. 5, 1967 United Kingdom 15692/67 M. W. Adriani, Rec. Trav. Chim. des Pays-Bas, V01. 35, No. 2 (1915), pp. 180-210.

H. W. Bond et al., J. Amer. Pharm. Assoc., Vol. 43, No. 1, pp. 32-35 (1954).

Primary ExaminerNorma S. Milestone Attorney, Agent, or FirmG0rdon W. Hueschen [57] ABSTRACT N-alkyl-N-9-xanthenylurea and substituted derivatives thereof useful in the treatment of peptic ulcer.

3 Claims, No Drawings XANTHEN DERIVATIVES vided compounds of formula 1 IDOI in which R is hydrogen, halogen, alkyl or alkoxy;

R is alkyl;

and R is hydrogen, alkyl, hydroxyalkyl, alkanoyloxyalkyl, alkoxyalkyl or alkanoyl;

and wherein the terms alkyl, alkoxy, al-

kanoyloxy and alkanoyl indicate such groups containing up to 7 carbon atoms.

Methods for the preparation of the compounds of formula I are described in detail in'our aforementioned U.S. patent applicationn Ser. No. 662,587.

It has been found that the compounds of formula I are antisecretory agents, with a specific activity against gastric secretion and without any anticholinergic activity. The anti-secretory activity has been demonstrated in the stimulated, pylorus-ligated rat, and varies with the values of R R and R The compounds of the invention may be administered orally, rectally or parenterally, preferably orally, the optimum dosage rate varying with the activity of the compounds. A preferred dosage rate for oral administration is of the order of 0025-2 g. daily, optionally in divided doses.

In use, the compounds of the invention are administered in conventional formulations, and therefore, according to a further aspect of the invention there are provided therapeutic compositions which comprise a compound of the hereinbefore described formula I in association with pharmaceutical excipients known for the production of compositions suitable for oral, rectal or parenteral administration.

The compositions of the invention preferably contain 01-90% by weight of a compound of formula I.

Compositions for oral administration are the preferred compositions of the invention, and these are the known pharmaceutical forms for such administration, such as for example tablets, capsules, syrups and aqueous and oily suspensions. The excipients used in the preparation of these compositions are the excipients known in the pharmacists art. Preferred compositions are tablets wherein a compound of formula I is mixed with an inert diluent such as calcium phosphate in the presence of disintegrating agents e.g. maize starch and lubricating agents e.g. magnesium stearate. Such tablets may, if desired, be provided with enteric coatings by known methods, for example by the use of cellulose acetate phthalate. Similarly capsules, for example hard or soft gelatin capsules, containing a compound of formula I, with or without other excipients, may be prepared by conventional means and, if desired, provided with enteric coatings in known manner. The tablets and capsules may conveniently each contain 25-500 mg. of a compound of formula 1. Other compositions for oral administration include for example aqueous suspensions containing a compound of formula l in aqueous media in the presence of a non-toxic suspending agent e.g. sodium ca'rboxymethylcellulose and dispersing agents, and oily suspensions containing a compound of formula I in a vegetable oil for example arachis oil.

Compositions of the invention suitable for rectal administration are the known pharmaceutical forms for such administration, such as for example suppositories with cocoa butter or polyethylene glycol bases.

Compositions of the invention suitable for parenteral administration are the known pharmaceutical forms for such administration, for example sterile suspensions in aqueous and oily media or sterile solutions in propylene glycol.

In the compositions of the invention the compounds of formula I may if desired be associated with other compatible pharmacologically active ingredients. For example antacids and acid absorbents such as aluminium hydroxide and magnesium trisilicate may be included in compositions for oral administration to give an immediate antacid efi'ect. Other pharmacologically active agents which may be associated with the compounds of formula I include compounds active on the central nervous system, including short and long acting sedatives such as the barbiturates and methaqualone,

antihistaminic and/or antiemetic agents such as cyclizine and diphenhydramine, and anticholinergic agents such as atropine.

Milk and milk solids are valuable in the treatment of peptic ulcer, and the compositions of the invention include liquid and solid compositions based on milk and milk solids.

For maximum stability, the compositions of the invention should preferably have a pH greater than 7; accordingly acidic excipients are not desirable.

In some formulations it may be beneficial to use the compounds of formula I in the form of particles of very small size, such as for example, as obtained by fluid energy milling.

According to another aspect of the invention there is provided a method of treating peptic ulcer which comprises administering to a patient 0.025-2 grams daily of a compound of formula I; in a preferred embodiment of this aspect of the invention, administration is by the oral route.

The starting materials employed in the preparation of compounds of formula I are in many cases known compounds; where they are new, they are prepared by methods analagous to those employed for known compounds, and as such will be apparent to those skilled in the art. By way of example the preparation of some new intermediates is given below.

PREPARATION l A solution of 9-formamidoxanthen (30.5 g.) in tetrahydrofuran (400 ml.) was added to a suspension of lithium aluminium hydride (5.2 g.) in tetrahydrofuran ml.) at room temperature. The mixture was stirred and refluxed for 5 hours, left to stand at room temperature overnight and then decomposed by the addition of water (5.2 ml.), N sodium hydroxide solution (4 ml.) and water (16.8 ml.). The suspension was filtered, the solid was washed with ether, and the combined filtrate and washings were evaporated. The residual syrup was dissolved in ether and extracted into 3N acetic acid solution (500 ml.) at 510C. The aqueous extract was basified, the oil which separated was collected in ether and the dried, ethereal extract was evaporated. The residue was distilled to give 9- methylaminoxanthen, b.p. (bath) 110C./0.1 mm.

Similarly 9-acetamidoxanthen was reduced to give 9-ethylaminoxanthen, b.p. l37140C/0.9 mm.

EXAMPLE 1 Ethyl isocyanate (1 ml.) was added to a solution of 9-methylaminoxanthen (2.02 g.) in methylene chloride (10 ml.). There was an exothermic reaction and after minutes at room temperature the solvent was evaporated. The residue was recrystallised from benzene to give N'-ethyl-N-methyl-N-9-xanthenylurea, mp. 139141C.

In a similar manner the following compounds are prepared:

N,N-dimethyl-N-9-xanthenylurea, m.p. 170-1 72C.

N-methyl-N'-propyl-N-9-xar1thenylurea, m.p.

N'-t-butyl-N-methyl-N-9 -xanthenylurea, m.p.

l 26l 27C.

N'-acetyl-N-methyl-N-9- xanthenylurea, m.p.

EXAMPLE 2 Methyl isocyanate ml.) was slowly added to a solution of xanthydrol (30 g.) and triethylamine (1 ml.) in benzene (120 ml.) at 65C. The solution was kept at 55C. until evolution of carbon dioxide ceased, refluxed for 1% hours, cooled and filtered. The solid was collected and recrystallised from benzene to give N,N- dimethyl-N-9-xanthenylurea solvated with 2 molecules of benzene, m.p. l70-l71C.

The solvate was dried to constant weight at 95C./2 mm, to give N,N-dimethyl-N-9-xanthenylurea, m.p. 173-174.5C.

In a similar manner there was prepared:

N,N-dimethyl-N-(2-chloro-9-xanthenyl)urea,

The following compounds were prepared similarly from the appropriate xanthydrol and isocyanate but using methylene chloride as the reaction solvent at room temperature:

N,N-diethyl-N-9-xanthenylurea, m.p. l25l27C N ,N'-dimethyl-N-( 1-methyl-9-xanthenyl)urea, m.p.

N-( 2-fluoro-9-xanthenyl )-N,N'-dimethylurea,

4 N-( l-chloro-9-xanthenyl )-N,N'-dimethylurea,

202206C N,N'-dimethyl-N-(4-methyl-9-xanthenyl)urea, m.p.

161-163C N,N-dimethyl-N-( 1-fluoro-9-xanthenyl)urea,

211212C N,N'-dimethyl-N-(2-methoxy-9-xanthenyl)urea,

m.p. 128-l29.5C

EXAMPLE 3 EXAMPLE 4 A mixture of xanthydrol (2 g.), N,N'-dimethylurea 1 g.), toluene (15 ml.) and acetic acid (0.6 ml.) was refluxed for 20 minutes, evaporated to dryness, the residue was washed with water and dried. It was recrystallised from benzene and the crystals dried at C./2mm. to give N,N'-dimethyl-N-9-xanthenylurea, m.p. 169-l70C.

In a similar manner the following compound is prepared:

N-( l-methoxy-9-xanthenyl)-N,N'-dimethylurea,

m.p. 178180C EXAMPLE 5 N-2-Acetoxyethyl-N-methyl-N-9-xanthenylurea (2.1 g.), methanol (20 ml.) and potassium cyanide (50 mg.) were refluxedfor 20 minutes and then evaporated to dryness. Recrystallisation of the residue from benzene and then from methylene chloride gave N-(2- hydroxyethyl)-N-methyl-N9-xanthenylurea as a hydrate, m.p. 132C.

In a similar manner the following compound is prepared:

N-( 2-hydroxyethyl)-N-methyl-N-( 2-methyl-9-xanthenyl)urea EXAMPLE 6 In the preparation of tablets, mixtures of the following type may be tabletted in conventional manner:

compound of formula 1 10-90% calcium phosphate 0-807: maize starch 5l0% magnesium stearate ca.1% microcrystalline cellulose 0-90% (by weight) EXAMPLE 7 The following mixture was formed into tablets in conventional manner, each tablet containing 50 mg. of active ingredient:

N,l 1-dimethyl-N-9-xanthenylurea maize starch -continued calcium phosphate 20% magnesium stearate 1% microcrystalline to 100% by weight EXAMPLE 8 In the preparation of enteric coated tablets, tablets prepared as described in Example 7 were coated with sanderac varnish and then coated with cellulose acetate phthalate using a solution of 20% cellulose acetate phthalate and 3% diethyl phthalate in a mixture of equal parts of industrial alcohol and acetone.

. EXAMPLE 9 In the preparation of tablets, the following mixture was dry granulated and compressed in a tabletting machine to give tablets containing mg. of active ingredient:

N,N'-dimethyl-N-9-xanthenylurea 10 g. lactose 5 g. calcium phosphate 5 g. maize starch 5 g.

EXAMPLE 10 In the preparation of enteric coated tablets, the tablets described in Example 9 were given a thin coat of shellac varnish followed by coats of cellulose acetate phthalate.

EXAMPLE I 1 In the preparation of capsules, a mixture of the ingredients described in Example 9 was encapsulated in hard gelatin capsules. Enteric coating was applied by conventional dipping in cellulose acetate phthalate.

EXAMPLE 12 The following mixture was compressed into tablets in a conventional manner:

N,N -dimethyl-N-9xanthenylurea sodium bicarbonate 75% peppermint oil q.s.

EXAMPLE 13 In the preparation of capsules, a mixture of equal parts by weight of N,N-dimethyl-N 9-xanthenylurea and calcium phosphate was encapsulated in hard gelatin capsules, each capsule containing 50 mg. of N,N'- dimethyl-N-9-xanthenylurea.

EXAMPLE 14 In the preparation of enteric coated capsules, the capsules of Example 13 were coated with cellulose acetate phthalate in conventional manner.

EXAMPLE 15 Suppositories weighing 1 g. and containing 50 mg. of N,N-dimethyl-N-9-xanthenylurea were prepared in conventional manner using a base consisting of:

polyethylene glycol 4000 33% polyethylene glycol 6000 47% water 20% EXAMPLE 16 A solution for parenteral administration was prepared by dissolving mg. of N,N'-dimethyl-N-9-xanthenylurea in 2 ml. of propylene glycol and sterilised by filtration.

Compositions similar to those described in Examples 6-16 were also prepared, containing the other preferred compounds described previously in place of N,N' -dimethyl-N-9-xanthenylurea.

We claim:

1. A compound represented by the formula I a N CO NHR 

1. A COMPOUND REPRESENTED BY THE FORMULA I
 2. A compound as claimed in claim 1 in which R0 is selected from the group consisting of hydrogen and alkoxy; R1 is alkyl; and R2 is alkyl.
 3. A compound in accordance with claim 1 which is N,N''-dimethyl-N-9-xanthenylurea. 